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  • Author or Editor: John M. Losonsky x
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Retrospective radiographic and scintigraphic analyses were performed on 27 fractures of the distal phalanx in 25 horses. Location of 99mtechnetium methylene diphosphonate (99mTc-mdp) uptake was compared with fracture line location as seen on radiography. Intensity (intense, moderate, mild) and pattern (focal, diffuse) of 99mTc-mdp uptake was recorded and compared with duration of fracture. Nine horses were monitored during convalescence by obtaining additional scintigraphic views 3 to 68 months after injury.

Palmar scintigraphic views had evidence of focal areas of increased 99mTc-mdp uptake that corresponded to fracture line location as seen on radiography. Lateral scintigraphic views had evidence of diffuse increased uptake. There was a significant (P < 0.01) association between duration of fracture and intensity of uptake, with fractures < 3 months in duration more likely to have intense focal uptake. All fractures < 10 days in duration had intense focal uptake. As fracture age increased, 99mTc-mdp uptake became less intense and more diffuse. Three fractures not evident on radiography had evidence of 99mTc-mdp uptake on scintigraphy. Stall rest resulted in decreased 99mTc-mdp uptake in 6 of 9 horses, but increased uptake was still visible in all horses between 4 and 25 months after injury. The only scintigraphic view without evidence of increased uptake was that obtained from a horse reexamined 68 months after injury.

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in Journal of the American Veterinary Medical Association



To document age-related changes in the morphology of the endodontic system, reserve crown, and roots of equine mandibular cheek teeth.


Equine mandibular cheek teeth from horses of various ages were compared, using radiography, x-ray computed tomography, and histologic examinations.

Sample Population

48 right hemi-mandibles from horses 2 to 9 years old.


Hemi-mandibles were radiographed, imaged by computed tomographic reconstruction, and reformatted. Histologic examination was used to identify and correlate tissue types.


Permanent mandibular cheek teeth of the horse, at the time of eruption, consisted of an exposed crown and a reserve crown with a widely dilated apex. The endodontic system consisted of 5 or 6 pulp horns that connected to an expansive pulp in the reserve crown, which was confluent with the primordial pulp bulb surrounding the tooth’s apex.

At the time of eruption, mandibular cheek teeth did not have a distinct pulp chamber, roots, or evidence of root formation. However, within 2 years after eruption, mesial and distal roots and a pulp chamber were present. A distinct pulp chamber, communicating with the pulp horns and both root pulp canals, was identifiable for 4 to 5 years from the time of root formation. The endodontic system of cheek teeth, 6 to 8 years after eruption, consisted of 2 unattached compartments, made up of a root canal, pulp chamber, and 2 or 3 pulp horns.

Clinical Relevance

The age-related morphologic changes in equine mandibular cheek teeth have important implications for application of endodontic therapy in horses. (Am J Vet Res 1996;57:31-38)

Free access
in American Journal of Veterinary Research


Navicular bone intraosseous pressure, gross pathologic, histologic, and histochemical data were collected from 8 horses with navicular disease and 4 control horses. Simultaneous navicular bone intraosseous, medial palmar arterial, and saphenous venous pressures were measured for the left and right forelimbs of each horse under general anesthesia. Gross pathologic evaluation included grading of changes on the flexor surface of the navicular bone. Safranin-O-fast green-stained sections were used for histologic-histochemical grading of the hyaline articular and fibrocartilage surfaces of the navicular bones. Hematoxyhn and eosin-stained sections were used for morphologic evaluation of the marrow spaces of navicular bones. Mean navicular bone intraosseous pressure for horses with navicular disease was significantly (P< 0.001) higher than that for controls. Differences in medical palmar arterial or saphenous venous pressures were not significant between groups. The median flexor surface gross pathologic and histologic-histochemical fibrocartilage scores for horses with navicular disease were significantly (P< 0.001) more severe than those for control horses. The histologic-histochemical hyaline cartilage scores for control horses and those for horses with navicular disease were not significantly different. Fibrosis of the marrow spaces beneath the flexor cortex of horses with navicular disease was more pronounced than that of control horses.

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in American Journal of Veterinary Research